Vitamin D Deficiency and Rickets:
- Prevalence of deficiency and insufficiency: 15% of the pediatric population.
- Vitamin D Physiology
- Daily recommended intake(healthy individuals)
- Infants (soon after birth): 400 IU/day
- 1-18 years: 600IU/day
- Definitions of sufficiency, insufficiency, and deficiency
- Vitamin D sufficiency: 20 to 100 ng/mL
- Vitamin D insufficiency: 12 to 20 ng/mL
- Vitamin D deficiency: <12 ng/mL
- Risk factors for deficiency
- Nutritional deficiency: maternal Vit D deficiency, a diet deficiency, exclusive breastfeeding
- Malabsorption: celiac disease, inflammatory bowel disease, cystic fibrosis
- 25-hydroxylase deficiency: liver disease, genetic disease
- 1,25-hydroxylase deficiency: renal disease, genetic disease
- Increased metabolism of Vitamin D-use of anti-seizure meds, steroids
- Other: CYP34A deficiency, Vitamin D binding protein deficiency, and obesity
- Clinical manifestations:
- Rickets in growing children.
- Severe vitamin D deficiency may lower serum phosphorus levels–> muscle weakness.
- 25 hydroxyvitamin D levels in the high-risk population.
- Treatment of mild vitamin D deficiency-cholecalciferol (D3) or ergocalciferol(D2)
- <12 months old – 1000 IU/day for 6 to 12 weeks, followed by maintenance dosing of at least 400 IU/day for 3 to 6 months
- ≥12 months old – 2000 IU/day for 6 to 12 weeks, followed by maintenance dosing of 600 to 1000 IU/day for 3-6 months
Definition: it refers to the changes at the growth plate caused by the deficient mineralization of bone before the closure of the growth plates.
- Calcipenic rickets: phosphorus concentration is normal or low, along with elevated PTH levels.
- Phosphopenic rickets: phosphorus level is low with normal PTH concentrations.
- Calcium, albumin, phosphorus, 25 hydroxyvitamin D levels, 1-25 dihydroxy vitamin D levels, PTH, spot urinary calcium/creatinine, alkaline phosphatase levels.
- Radiological: X-ray of wrists.
Anticipatory Laboratory Values for different types of Rickets
|PTH||Alk Phos||25(OH) Vit D||1,25(OH2) Vit D|
|Vitamin D deficiency||↓/↔||↓/↔||↑||↑||↓||↔|
|1 alpha-hydroxylase def||↓||↓/↔||↑||↑||↔||↓|
|Vitamin D Resistant||↓||↓/↔||↑||↑||↔||↑↑|
- Treatment: It depends on the type of Rickets.
- Chole/Ergocalciferol-1000-9,000IU/day for Vitamin D deficiency rickets.
- Add calcium at a dose of 30-75mg/kg/day if hypocalcemia is present.
- Vitamin D resistant and 1 alpha-hydroxylase rickets are treated with calcitriol.
- For the treatment of hypophosphatemic rickets, calcitriol(higher dose) is given along with phosphorus supplementation.
- Monitoring requires monitoring of calcium, phosphorus, alkaline phosphatase, and parathyroid hormone levels in 2-3 weeks.
References and Resources
- Munns CF, Shaw N, Kiely M, et al. Global Consensus Recommendations on Prevention and Management of Nutritional Rickets. J Clin Endocrinol Metab 2016; 101:394.